Actix-web: How to customize error for web::Json<T> deserialzation errrors?

[gh67uyyghj]

If the payload is invalid, the server throws back to the user a message e.g. Json deserialize error: invalid type: Z, expected a string at line X column Y, this is extremely undeseriable in production. I know there is JsonConfig but this works only per each T so it's pointless and exhausting to initialize it for each API endpoint, there should be a way to make this error handling global or anything that works at the App level. Is there any workaround or a solution for this as of the latest sable release? Thank you.

[onelson]

Seems a bit like this is really an issue for the maintainers of serde_json to improve the error it returns on a parse failure.

Even if I were to customize per T, I'm not quite sure how I'd reason about giving useful more feedback, at least in a generic or procedural way.

[gh67uyyghj]

@onelson thank you for the response, I am not concerned about the exact error produced by serde, I am concerned actually about not throwing off that kind of revealing messages like (Json deserialize error: invalid type: Z, expected a string at line X column Y) about the system, I just want to override whatever error produced by the deserializer and replace it with some custom json message compatible with my API design. Something like "{"error": "deserialization error"} that works at the App level

[alu]

@gh67uyyghj You can registeir your original error handler. Check below.

https://docs.rs/actix-web/1.0.9/actix_web/web/struct.JsonConfig.html

[gh67uyyghj]

@alu thank you, I know of this solution but as I said in the post this works per type, I must repeat this for each handler that accept json body requests, which is pretty much the entire API. I was asking if any generic solution actually currently exists at the App or Service level.

[alu]

@gh67uyyghj
You can register custom error handler as default such as below.

App::new()
  .data(web::JsonConfig::default().error_handler(|_, _| ...)))

[gh67uyyghj]

@alu wow thank you! this totally resolves my issue. Thanks.

[foisonocean]

@alu I'm using actix-web 2.0.0, and it seems that

App::new()
  .data(web::JsonConfig::default().error_handler(|_, _| ...)))

doesn't work, when serde failed to parse the JSON, the custom error handler I write won't be called. Anyone has any idea about this?

[s97712]

@alu I'm using actix-web 2.0.0, and it seems that

App::new()
  .data(web::JsonConfig::default().error_handler(|_, _| ...)))

doesn't work, when serde failed to parse the JSON, the custom error handler I write won't be called. Anyone has any idea about this?

+1

[PeterUlb]

@alu I'm using actix-web 2.0.0, and it seems that

App::new()
  .data(web::JsonConfig::default().error_handler(|_, _| ...)))

doesn't work, when serde failed to parse the JSON, the custom error handler I write won't be called. Anyone has any idea about this?

Still works with .app_data()